Your right. It wouldn't help a great deal in this particular case.

The problem I had trying to access it without resorting to XS came (I was reliably informed) because it (or at least the version exported by perl56.dll under AS/build633multi-threaded) requires that it is passed a pTHX_ SV* rather than a simple SV* as shown below and it isn't possible to get at one of those from within Perl itself. I could well be wrong on that, but I failed spectacularly for 3 days to achieve it.

PERL_CALLCONV I32    Perl_looks_like_number(pTHX_ SV* sv);
[download]

As for the XS. I am not, nor do I wish to be at this point, set up to go through the pain of building my own XS modules. I am managing to keep myself busy trying to learn the in's and out's of perl itself. A process which I am thoroughly enjoying. I don't wish (at this time) to pollute that joy by getting into the world of XS which I have seen several monks who's abilities I much respect, complain publicly (though possibly in part in jest) regarding the vaguries of using XS.

Thanks a lot for the offer though. I wonder, but don't have enough insentive at this stage to research it, how hard it would be to create a module that would reliably work cross platform?

Please excuse my ignorance if what you offered would do that, but I mean one that I could install with the need to compile it.